Buy more iCloud storage and back in Apple's cloud, probably the easiest solution.
Expand your Macbook storage with a Transcend Jetdrive SD card that fits flush with your Mac and gives you up to another 256GB (Though if it's the new Macbook I think that only has the one USB C port so not an option there).
Best solution and so useful for sooooo many other things is your own NAS drive. Both Synology and Qnaps would get my recommendation. You can have network shares that your Macbook will always be connected to when on your local network and you can even setup remote access to them if you need it when out at other locations. Plus you can do time machine backups and many many more things on top.